共查询到18条相似文献,搜索用时 62 毫秒
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针对H.264帧间预测时的多子块模式选择和帧内预测的多模式选择问题,提出了一种实用的基于统计门限的模式快速选择算法,通过门限设定有效限定了编码模式的选择范围.多组视频序列的实验结果表明,基于统计门限的帧内预测模式选择算法在Ⅰ帧的PSNR值有微小变化的情况下,大大降低了编码时间,Ⅰ帧的编码时间降低17%~23%,PSNR下降不到0.4%.基于统计门限的帧间块模式选择算法使得平均PSNR值下降了0.047dB(PSNR最大下降不到1%),但是相对全模式预测时,编码器速度提高了20%~30%. 相似文献
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一种基于预测模式的H.264/AVC视频信息隐藏改进算法 总被引:3,自引:0,他引:3
提出了一种基于帧内预测模式调制的H.264/AVC视频信息改进隐藏算法.选择参考像素亮度值接近的帧内4×4块,通过对预测模式值进行调制以实现隐秘信息的嵌入,而预测模式调制过程是将最优预测模式变为满足嵌入条件的具有率失真开销最小的预测模式,以尽量减小预测模式的改变对视频客观质量的影响.信息的提取过程不需要原始载体视频,也... 相似文献
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基于编码模式的H.264/AVC视频信息隐藏算法 总被引:4,自引:0,他引:4
本文提出一种基于编码模式的H.264/AVC信息隐藏方法,通过调制某些宏块的编码模式,分别在Ⅰ帧、P帧和B帧中嵌入隐秘信息.对帧内4x4预测模式的宏块,是通过调整宏块中某个4×4块的编码模式嵌入隐秘信息;对P帧和B帧其它类型的宏块,则是通过调整宏块的编码模式嵌入隐秘信息,模式调整后对宏块做了优化处理.在模式调制过程中引入率失真代价,取得了较好的率失真平衡,减小了隐秘信息嵌入后对视频质量和视频码流的影响.该算法可以实现隐秘信息的快速提取,满足视频实时处理的要求,实验仿真结果证明了该算法的有效性. 相似文献
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《成像科学杂志》2013,61(3):311-319
AbstractIntra coding is used for reducing the spatial redundancy in video coding. H.264 supports several macroblocks of predictions for intra coding such as luma block four 16×16 modes, nine 4×4 modes and chroma block four modes, which significantly improve intra coding efficiency, but increase the encoding complexity. In order to select the best mode, we need to calculate the cost of the various modes. In this paper, a fast intra prediction mode decision for H.264/AVC video coding is proposed. Based on Laplacian, this intra prediction mode decision detects edges and selects the best mode for the block. This mode decision can shorten the time to reduce the encoding time. The experimental results show that the proposed algorithm achieves an encoding time saving of 70% on average. 相似文献
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提出了一种在隔行扫描MPEG-2视频流中嵌入DCT域水印的算法。该算法对MPEG-2中DCT变换按帧和按场进行的两种情况采用不同的扩频码进行嵌入和检测,使水印的检测基本不受DCT方式变化的影响,从而能够抵抗各种重编码攻击,同时也保持了良好的实时性。还采用了两步算法,即除水印数据外还同时嵌入了少量同步信息,这样既可定期更新用于水印数据的扩频码,从而提高算法的安全性与灵活性,同时在存在帧插入/删除等攻击时又不会因失去同步而导致检测失败。 相似文献
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Performance improvement of multi‐view video coding based on geometric prediction and human visual system
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Mian‐Shiuan Li Mei‐Juan Chen Chia‐Hung Yeh Kuang‐Han Tai 《International journal of imaging systems and technology》2015,25(1):41-49
This article proposed an accurate disparity vector prediction (DVP) algorithm for multi‐view video coding. Differing from traditional DVP that uses the information of motion vectors of neighboring blocks, the geometry of the camera position is utilized to calculate the parallax of different viewpoints in this algorithm and this parallax is the foundation of DVP. We jointly applied the Just‐Noticeable‐Difference human visual model to the DVP. After filtered using Gaussian function, the geometric DVP was obtained. Experimental results showed that the proposed method achieved significant data reduction and subjective/objective quality enhancement. © 2015 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 25, 41–49, 2015 相似文献
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为了实现有效与可靠的视频传输,针对水下单光子通信系统,提出了一种基于字典学习和LT码级联LDPC码的视频联合编码方案。通过字典学习稀疏编码,极大地压缩了视频数据量。根据水下单光子信道存在的删除特性,利用LT码级联LDPC码的信道级联编码方法,同时克服了LT码译码开销过大的缺点。由于LT码存在译码失败概率的问题,提出了译码成功双反馈机制。实验结果表明,当信道误码率处于10-2数量级、视频压缩率为75.6%时,可以实现平均峰值信噪比(PSNR)为37.4921 dB重建视频帧。 相似文献
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针对最新的视频编码标准H.264,设计了一种基于差错估计的容错算法。该算法结合信道条件,估计差错在视频编码帧之间的扩散;根据每个宏块差错的程度,自适应地判断是否对该宏块进行帧内编码,从而抑制差错的积累。在存在反向信道的环境中,该算法可以利用解码器反馈的实际宏块错误信息,跟踪差错扩散,对其进行更准确的估计,以提高容错性能。仿真表明,在各种信道条件下,该算法相对于随机帧内宏块更新算法.重建图像平均峰值信噪比有1.3~2.5dB的提高。同时,该算法对信道估计的要求不高,运算量和存储量的增加较低,具有实用性。 相似文献
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Seung‐Hwan Kim Yo‐Sung Ho 《International journal of imaging systems and technology》2006,16(4):113-120
In this paper, we propose a new efficient bit‐plane coding method for fine granular scalable (FGS) video coding. The general structure of the proposed bit‐plane coding method is based on the traditional bit‐plane coding scheme in MPEG‐4 FGS. However, to enhance coding efficiency of bit‐plane encoding, we apply an efficient probability estimation scheme through employing the binary arithmetic coding. For probability estimation, various context models are designed to take advantage of the characteristics of each bit‐plane as well as the correlations of symbols among different bit‐planes. Experimental results show that the proposed FGS coding scheme provides better coding performance, compared to the well‐known FGS coding schemes in MPEG‐4 FGS and JSVM. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 16, 113–120, 2006. 相似文献
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In this paper, an effective intra prediction mode-based video strganography is proposed. Secret messages are embedded during the intra prediction of the video encoding without causing large embedding impact. The influence on the sum of absolute difference (SAD) in intra prediction modes (IPMs) reversion phenomenon is sharp when modifying IPMs. It inspires us to take the SAD prediction deviation (SPD) to define the distortion function. What is more, the mapping rule between IPMs and the codewords is introduced to further reduce the SPD values of each intra block. Syndrome-trellis code (STC) is used as the practical embedding implementation. Experimental results demonstrate that our proposed steganographic scheme presents high undetectability compared with existing IPMs-based steganographic approaches. It also outperforms these schemes on stego video quality. 相似文献